In order to safely use a battery in a hazardous environment, such as coal mines where the possibility of explosions exits, a safety feature is needed to prevent spark generation when the battery contacts are inadvertently shorted. Conventional batteries for portable two-way radios used in such environments, incorporates protective circuitry to achieve this safety feature. The protective circuitry, upon detection of a short on the battery positive and negative contacts, provides for an open circuit between one of the cells terminal and the corresponding battery contact, thereby preventing spark generation. Although the current protective circuitry insures protection when the battery contacts are shorted, no provision exists to test the functionality of the protective circuitry prior to use in the hazardous environment. Thus, a portable radio user may not know that the protective circuitry has failed and mistakenly believe that that the radio and battery are safe.
Additionally, intrinsically safe batteries and non-intrinsically safe batteries have the same general appearance. Therefore, these batteries are usually distinguished from one another by a label placed on the battery housing. This distinguishing method may cause confusion during manufacturing or during use of the battery, causing a factory operator (or a user) to inadvertently place a non-intrinsically safe battery on a radio designated for use in hazardous environments. Therefore, a more reliable distinguishing method is desirable.